Magnet



H. S. FOLKER May 13, 1930.

MAGNET H. S. FOLKER May 13, 1930.

MAGNET Filed Feb- 12. 1926 2 Sheets-Sheet INVENTO'R Harm/70 \5. F04 my? Pga qw d

WITNESS W Patented May 13, 1 930 UNITED STATES PATENT OFFICE HOWARD FOLKER, OF MILL VALLEY, CALIFOEI L E'IA, ASSIGNDE, BY ASSIGN- MENTS, TO NATIONAL SAFETY A'PPLIANOE COMPANY, OF RENO, NEVADA, A COR- PORATION OF NEVADA MAGNET Application filed February 12, 1928.

This invention relates to magnetic structures and more particularly to an improved tiaclt magnetadapted to be positioned be tween the rails oi" a railroad track, so constructed and arranged that its normal magnetic field may not only be neutralized or diverted but may be increased or strengthened at Will so that the operation of various forms of magnetically responsive devices, which are installed upon the train or engine, may be controlled or effected by means oi the said magnetic fields.

This invention is an improvement upon that disclosed in my co-pending application, Serial l lo. 574,920, filed July 14th, 1922, which an )licaticn discloses a structure emiagnetic means is on open circuit, field Will exist in the air surroundo be eii'ective to control the opermagnetically responsive device 1 i positioned on the train or engine 'tion to the tracl: magnetic structure,

in magnet is so neutralized or deflected be ineffective to control the operot' the said responsive device, the reaticn spo ve vice, particularly in view in the vs a c led application, being the brake control a paratus of a moving train.

J2 er object of that invention Was to provi 'net produce an effective field suliic n; length, uniformity and symmetrical di mention to insure actuation of the controller: means for the responsive device of rapidly moving trains, and which would also permit the neutralization of the field as aforesaid, with sufficient uniformity to insure the non-operation of the said con- Serial No. 87,769.

this for ll c e on that for certain purposes in au'o? train control it is necessa y to provide i the action of more than one conce on the tra F or example, '1 conditions, it may be desirable rocecd under automatic control 1 1 21 we 1 b Wen centre 0mg initiated y of a given device on the train.

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the action Then, when a point is reached beyond Which el; is ndicated different actuation, or an act ation of a dilierent device, necessary to remove the speed control.

iliccordingly, the object of the present inv ion is to provide a single track magnetic cc of the general character of that dein the aforesaid pending application that all the benefits derived thereacove po' ited out, Will be retained,

-11 i so modified and improved as to urovich for the difij'erent actuations ot' the o 7 ext control devices on the train.

r us forms. of magnets, comprisiermaiiont magnet structure and assomrcmagnetic means, may be used out the present invention, yet for ion of automatic train control api t pe which includes magnetic: llv uc d and magnetically operated control 1 '7 form oi magnet structure is that described in the above referred to pending application.

Referring to the drawings forming part of this specification:

Fig. 1 illustrates magnet, including its electric circuits, embodying one form of my invention.

2 is a fragmentary view showing one side of my improved magnet, with electric circuits, embodying another form of my invention.

Fig. 3 is a side elevation of the track magnet, portion of the apparatus being shown in section.

Fig. 4; is a plan illustrating the position of the track magnet between the rails of a rail road track in its relation to the floating train magnetic controlling device.

he magnet M is designed to be in the center of the track rigidly secured to the road bed and sleepers S, the equalizing bars 10 and 12 thereof lying parallel to the rails R and 1, all as illustrated in Fig. 4.

The equalizing bars 10 and 12 are con structed of magnetic material and are attached to the poles of the permanent magets 16, 18, 20 and 22, the north poles being connected to one bar, as 10, and the south poles being connected to the other bar as 12.

The electromagnets 28, 30 and 32 have the ends of their cores 3% mechanically attached to the equalizing bars but magnetically separated therefrom by suitable interposed reluctances 39, and, as clearly shown, the end electromagnets 28 and 32 are spaced nearer to the end permanent electromagnets 16 and 22, respectively, than the intermediate permanent and electromagnets are to each other in order to obtain a more uniform distribution of the magnetic potential along the equalizing 10 and 12. With no current flowing in the windings 40 of the electromagnets, the fluxes 01" the permanent magnets divide themselves between the cores of the electromagnets, limited in that path by the reluctances, and the air gap separating the said equalizing bars.

That part of the flux, constituting what may be termed the normal field, is effective for the operation of a suitable magnetically responsive device, carried by the cara train, and brought or positioned within its ran 'e, and which is conventionally illustrated in Fig. d at F. The general operation is well understood by those skilled in the art and is described in my prior Patent No. 1,439,081, dated December 19th, 1922.

hen current of proper value is caused to flow in the windings, by the closing of the circuit circuit controller 100, in such a direction as to magnetize the cores with polarity opposite to that of the permanent magnets, the flux passes almost entirely through the cores and the field is neutralized or delloctod or diminished to such an extent as to be inetlective for operation of the responsive device.

I have found that a suflicientand quite practicable flow of current in the direction opposite to that just specified will magnetize the cores with polarity like that of the permanentmagnets and will produce a magnetic field, which may be called a super-field, which is very much stronger than the normal field of the permanent magnets, and which, of course, is of the same polarity. By so doing, a magnetic field is produced which is suiiiciently stronger than the magnetic field of the permanent magnets alone as to he satisfactorily utilized for the operation of a train device, such as F in Fig. i, which would be unatl ected by the normal field of the permanent magnets alone. 7

It is obvious that a control valve or other magnetically responsive d vice can readily be so constructed, positioned or adjusted on the train that it will be operable by the strong super-field and not operable by the relatively weak-er normal .tield.

With the track magnet here described, for the purpose of illustration, a reverse current equal to that required for satisfactory deflection or neutralization of the normal magnetic field may be obtained by closing the circuit at the controller 200. field ct substantially twice the strengtn of the normal field will thus be produced. The limits or the two fields are well separated to give ample margin tor a reliable operation by the one and nonoperation by the other.

l have thus proviced tor the magnetic op eration, from a sh e magnet structure, of two train devices, one of which is arranged to respond to the super-field only and to be unaffected by the normal field, while the other responds not only to the normal but also to the super-field as well. The operation, however, is selective least to the extent, sutficient for some purposes, that a certain one of two train devices can be operated alone or the two can be operated together as con ditions controlling the electric circuit of the magnet may determine.

l Vhen certain conditions require the nonoperation of both of the operable train devices, the two sources o1 current may be oppositely connected so that the closing oi the circuit controller 160 and the opening of the circuit controller 200 will cause the magnetic field oi the permanent magnet to be diverted or neutralized. ll hcn both of the circuit controllers are open, however, the normal field of the permanent magnets will. exist, and upon the closing of: the circuit controller 200 and the opening of the circuit controller 100, the super-field will be produced.

Where it is desired therefore to utilize the two fields only the arrangement may be that shown in l in whicn there are two sources 0t current B and B, and in which the source of current B is assumed tobe so connectedthat when the circuit is closed at the circuit controller 200 and open at 100 the flow of current will be in the right direction to produce the super-field. The normal field will be present when both circuits are open, and the super-field will replace it when the circuit including the source of current B is closed.

As an alternative, the arrangement shown in 2 may be used with one source of current B and a pole-changer 300, by means of which the circuit may be opened whereby the normal iield will exist, or it may be closed with either polarity, thereby neutralizing or diverting the normal field or else adding to it to produce the super-field.

The circuit controller or pole-changer may be of any type and operated in any manner suited to a particular application of the in.- vention. in the case of automatic train control, for example, it may be operated by a signal or the controllers may be the contacts of a relay forming part of, or an addition to, a signal system. So, also, may the magnet structure take various forms in various applications, with one or more oermanent mag-- nets and one or more electro-magnetic eleme and it may be constructed either with or wi hout pole pieces or equalizing bars.

The general structure and the operation ol the device ha ring been clearly set forth above, its spcciiic structure will now be definitely pointed out to enable anyone skilled in the art to ronstruct the magnet.

A pair oi. magnetic equalizing bars and 12 of sott iron are adapted to be positioned between the rails of the track and are charged with opposite polarities by means of the permht magnets 16, 18, and which are spaced through the length oi the bars, it'our magnets eing shown *1 the ei'nbodiment oi the in. tion illustrated the drawings. For this purpose, the positive, or north poles of all of the magnets are rigidly mounted on, or connected to, one oi the bars, as for 'niple, bar 10, by means 01" clips preterably oi non-magnetic material, and screw threaded bolts 26, and the other, or south poles, are similarly connected to the bar 12. Throug the uigement of the permanent magnets relatively to the equalizer bars, the bar 10 is charged inductively with one polariy and the bar 12 charged inductively with he opposite polarity.

.ln the preferred embodiment of the inven tion the permanent magnets 16, 18, and 22 are formed of a'nimber of straight bars 4-8, which, however, may be of horse shoe or other ble shape, and are held in spaced relation to each other by means of end clamps ably ct non-magnetic material and i5 members 5 erably or non therebetween. material which re- 1 are made of a tains its ma netization, such for example as hard steel.

The magnetic charges of the bars 10 and 12 are either neutralized or increased by means of electromagnets 28, and 32, suitably spaced along the length of the bars which, when energized by means of the current from the battery or generator B upon the closing of the circuit controller 100, will have a polarity opposite to that of the permanent magnets 16, 18, 20 and 22. To this end, each electromagnet is provided with a soft iron core 34%, the ends of which are mounted in pole pieces 36, preferably of high permeability by means of a pressed tit and by peening the ends of. the cores over the pole pieces, and are supported on the bars 10 and 12 by means of bolts 38 ot non-magnetic material extending through holes in the pole pieces and the bars. The pole pieces 36 are also preferably spaced from the bars 10 and 12 by spacing means 39 of brass or other nonmagnetic material to obtain the desired reluctance for proportioning the magnetic flux between the cores of the electromagnets and the air above the equalizing bars. Each electromagnet is PI'OVlClGCl with a winding 10 ot insulated wire wound on its core 34 and impregnated with an insulating compound, and retained on each core by means of discs 52 of non-conducting material which form spool ends for the windings. The windings are covered and protected by means of cylindrical casings 54 or housings of nonmagnetic material slightly spaced from the outer layer of the windings and closed by end caps 56 of non-magnetic material hermetically sealed on the ends of the casings and holding the. cores and casings in spaced relation to each other. The space between the winding and the wall of the casing is filled with insulating material 58.

As stated above, normally the north poles of the permanent magnets are connected to the bar 10 and their south poles to the bar 152.

In the preferred embodiment, therefore, when the circuit controller 100 is closed (the controller 200 being open) by operation of the battery or generator B. the positive, or north poles, of the clectromagnets will be adjacent to the bar 12 and the negative, or south poles, of the electromagnets will be adjacent the bar 10, thus producing a neutralized or deflected field, and when the controller 200 is closed with the controller 100 open, and the current flowing from the battery or generator B, the positive, or north poles of the electromagnets will be adjacent the bar 10 and the negative, or south, poles will be adjacent the bar 12, thus producing the superfield, and when both circuit controllers are open the normal field of the permanent magnets is alone effective as above described.

A suitable wiring arrangement for energizing the electromagnets is illustrated diagrammat-ically in Figs. 1 and 3 of the accompanying drawing, in which the windings are connected by the wires 41, 4:2 and 4:3 in series between the terminals of a source of electricity B, such as a battery or other suitable generator. The circuit being closed by the circuit controller 100, the degree of magnetization is controlled by adjusting the current passing through the windings by means of a variable resistance or rheostat 44;, to permit the electromagnets to neutralize or deflect the field of the permanent magnets.

Another circuit is also provided between the wiring 11 and the battery B, the circuit controller 200 and the rheostat 44 by means of the wiring 4:11 and 4:12. Upon the closing of the circuit at 200, the circuit at 100 being open, the magnetism of the electromagnets will add to the magnetic force of the permanent magnets, thus effecting a super-field by adding the field of the electromagnets to the field ot' the permanent magnets.

The same operation may be gained by the use of a single battery or generator B and by the interposition of a pole-changer 300 properly insulated as shown in circuit so that the circuit may be opened or may be closed with either polarity. In such a winding, the wires 11 are caused to permit the current to travel in reversed directions, depending upon the contacts which are closed by means of the pole-changer. hen the terminals a and a of the pole-changer contact respectively with the terminals Z) and Z) in the wiring, the electromagnets will be energized with one polarity to deflect or neutralize the field of the permanent magnets, whereas when the terminals a and a of the pole-changer contact with the terminals Z) and b in the wiring, the electromagnets will be energized with a polarity opposite to that first mentioned to effect the super-field, and when the terminals a and a are disconnected from the contacts, then the permanent magnets operate to pro duce the normal magnetic field.

As changes of construction could be made within the scope of my invention, it is intended that all the matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is 1. A magnet of the type described which comprises a pair of magnetic equalizing bars, spaced permanent magnets spanning said equalizing bars, the south poles of said mag nets being connected to one bar and the north poles to the opposite bar, spaced magnet cores spanning said bars to provide a return circuit having reluctance to the flux of said permanent magnets, and an electric circuit includ ing solenoids about said cores and adapted to provide an electro-magnetic field to strengthen that of said permanent magnets or a reversed electro-magnetic field to increase the permeability of said return circuit through said cores. V

2. A magnet of the type described which comprises a pair of magnetic equalizing bars, spaced permanent magnets spanning said equalizing bars with the south poles of said magnets connected to one bar and the north poles to the opposite bar, electro-magnetic coils spanning said bars, and means for passing current through said coils in a direction to strengthen the magnetic fields of said permanent magnets or to provide a high permeability to the return of magnetic flux through said electro-magnetic coils.

3. A magnet of the type described which comprises a pair of magnetic equalizing bars, spaced permanent magnets spanning said equalizing bars, electro-magnetic coils spaced between and approximately parallel to said permanent magnets, and means for passing an electric current through said electromagnetic coils in one direction to increase the magnetic flux of said permanent magnets or to pass current in the opposite direction to increase the permeability to return or magnetic flux through said electro-magnets.

a. A magnet of the type described which comprises a pair of magnetic equalizing bars, permanent magnets spanning said equalizing bars and spaced at intervals in the length of said equalizing bars, cores spaced between said permanent magnets and approximately parallel therewith to provide a return mag netic circuit having reluctance thereto, electro-magnetic coils surrounding said cores, and means for passing electric current in one direction through said electro-magnetic coils to increase the magnetic flux and alternatively to pass current in the opposite direction through said coils to increase the permeability through said return circuit.

5. A magnet of the type described which comprises a pair of magnetic equalizing bars, permanent magnets spanning said equalizing bars and spaced at lengthwise intervals thereof, the south poles of said magnets being connected to one bar and the north poles to the opposite bar, and electro-magnetic means between said permanent magnets to provide a return circuit of low permeability, and means for passing an electric current through said electro-magnetic means in one direction to reinforce the magnetic flux of said permanent magnets or to pass an electric current through said electro-magnetic means in the opposite direction to provide a return circuit of high permeability for said magnetic flux.

6. A magnet of the type described which comprises a pair of magnetic equalizing bars,

permanent magnets spanning said equalizing bars at intervals spaced lengthwise of said equalizing bars and secured to the under side of said equalizing bars, the south poles of said magnets being connected to one bar and the north poles to the opposite bar, magnetically permeable cores spaced between said permanent magnets and secured to the under faces of said equalizing bars, a spacing means having a magnetic reluctance between the ends of said cores and said equalizing bars, electromagnetic coils about said cores, and means for aassing electric current through said electromagnetic coils in either direction or to open the circuit of said electro-inagnetic cores to strengthen the electro-magnetic flux of said permanent magnets, to provide a return circuit of high permeability, or to provide a return circuit of low permeability between said equalizing bars.

HOWARD S. FOLKER. 

